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Re: [Xen-devel] [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

On 8/10/2015 4:26 PM, Wei Liu wrote:
On Mon, Aug 10, 2015 at 11:33:40AM +0800, Yu Zhang wrote:
Currently in ioreq server, guest write-protected ram pages are
tracked in the same rangeset with device mmio resources. Yet
unlike device mmio, which can be in big chunks, the guest write-
protected pages may be discrete ranges with 4K bytes each.

This patch uses a seperate rangeset for the guest ram pages.
And a new ioreq type, IOREQ_TYPE_MEM, is defined.

Note: Previously, a new hypercall or subop was suggested to map
write-protected pages into ioreq server. However, it turned out
handler of this new hypercall would be almost the same with the
existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and there's
already a type parameter in this hypercall. So no new hypercall
defined, only a new type is introduced.

Signed-off-by: Yu Zhang <yu.c.zhang@xxxxxxxxxxxxxxx>
  tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++---
  tools/libxc/xc_domain.c          | 59 ++++++++++++++++++++++++++++++++++++++--

FWIW the hypercall wrappers look correct to me.

diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index 014546a..9106cb9 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -329,8 +329,9 @@ struct xen_hvm_io_range {
      ioservid_t id;               /* IN - server id */
      uint32_t type;               /* IN - type of range */
  # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
-# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
+# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
  # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func range */
+# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */

This looks problematic. Maybe you can get away with this because this is
a toolstack-only interface?

Thanks Wei.
Well, I believe this interface could be used both by the backend device
driver and qemu as well(which I neglected).  :-)



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